The present invention relates to a door operating mechanism for operating a door relative to a box-shaped base, and a unit including the same. As used herein, the term “box-shaped base” is interpreted broadly to include various types of storage body, housing and the like, and the term “door” is also interpreted broadly to include lid, cover and the like.
A door operating mechanism, including a door that is rotatably switched between the closed and open positions relative to the opening of a box-shaped base, via a shaft or the like, is not attractive and is less sophisticated in appearance, as the door projects extensively from the base in the open position.
Such a door operating mechanism and the unit including the same, as shown in FIGS. 8(a) and 8(b), were developed by the present inventors in their effort to remedy such shortcomings, as provided in Japanese Patent Laid-open Publication No. 2003-129742 (“JP 2003-129742”).
The door operating mechanism, as shown in FIGS. 8(a) and 8(b), as employed in the box 1, comprises a biasing means 5 to bias the door 3 towards the open position, lock means 4 to lock the door 3 against the bias force of the biasing means 5, and damper means 6 for applying damping force.
The base 2 is bordered with a flange 26 on the upper side, and the side walls thereof, located in the rear portions 23a, extend outward beyond those in the front portions 23b. A window is formed in one end surface of the extending section to allow for communication between the outside and the inside.
The door 3 has a support arm 31 so arranged as to come out from the interior of the base 2 through the aforementioned window. The damper means 6 is attached to the disc 32 of the arm 31. The lock means 4 locks the engaging piece 34 of the door 3 with a push operation, and unlocks it with another push operation.
The biasing means 5 is secured to a projection 29 of the base 2 at one end, and the shaft 35 of the arm 31 at the other end. The characteristics of this mechanism, as shown in FIG. 8(b), i.e., which in an enlarged schematic diagram, include the following. The mechanism has a sector gear 37 disposed in the arm 31 of the door 3 and a rotary gear 7 disposed in the center of the arc of the gear 37. The rotary gear 7 includes the damper means 6. In addition, the base 2 has a first stationary gear having internal teeth 27a disposed in the sector rib 27, in order to engage with the gear 37, and a second stationary gear 28 disposed inward from the first stationary gear 27a, to engage with the rotary gear 7.
In the operation of the above described mechanism, the door 3 is moved along the track of the internal teeth of the first stationary gear 27a, during which movement, the engagements between the gear 37 and the first stationary gear 27a, and between the rotary gear 7 and the second stationary gear 28, are maintained. By moving the fulcrum of the door 3 up or down in compliance with the internal gear (and the gear section of the second stationary gear 28) while the door 3 is rotatably switched from the closed position to the open position, and vice versa, the amount of the door 3 projecting from the interior of the base 2 can be reduced. In addition, during the process of rotational switching, a decent operation can result from the damping force applied by the damper means 6 and the respective engagements between the gears.
However, in the door operating mechanism, and the unit including the same described above, when the door is subjected to a large load F from above while in the closed position, the load conveys to the rotary gear 7, which is engaged with the second stationary gear 28 of the base. This may potentially damage the section or the support of the rotary gear 7 that is engaged. Where the rotary gear 7 is mounted to the output shaft of the damper means 6, the load may cause oil, which is included with the damper means 6 and fills the damper body, to leak.
These deficiencies become more prominent when the door 3 is to also serve as an arm rest, a simple table, or the like, in addition to cases where an object is inadvertently dropped or rested on the door 3.
It is therefore an object of the present invention to solve the problems described above to thereby eliminate possibilities of damaging or breaking the rotary gear or the related members and gears, while improving the quality and reliability, without limiting the applications.
Other objects of the present invention will become apparent from the description of the invention as provided below.